On Monday, February 4, 2019 at 4:08:41 PM UTC-5, John Godfrey (QT) wrote:
The 2019 proposed US competition rules reduce the turnpoint radius for the Assigned Task to 0.5 sm from 1 sm (a reduction of the turnpoint area of 75%).

This change also applies to the MAT task turnpoints.

Reducing the MAT radius, where gliders may be approaching a turnpoint from many different points of the compass, doesn't seem like such a good idea to me from a safety perspective.

QT

Wellllll, some of us can remember when it was 0.25 SM radius, and we lived through that....

I'm guessing the motivation was to make US turnpoints more FAI like?

The important difference between USA and FAI AT turns isn't the radius, it's how distance is calculated.

The FAI turn is "tag and go" (just like that 0.25 SM radius turn was, circa 1999). Some famous RC guys maintain this is dangerous because it drives all the gliders towards a single point (because there is no benefit to penetrating the turn). Others maintain that this is in fact safer (on an AT) because it makes pilots more predictable. Lately, I incline towards the latter view. The US style turns (which are simply small area turns, distance scored to best fix) sometimes tempt guys to get cute.

I agree that shrinking the MAT turn size isn't a good idea.

The main change that could benefit safety on MATs (if we still have to have them at all) is in task calling guidance. The practice of assigning not quite enough turns to fill out minimum time and having the last assigned turn close to home base yields a very weird and sometimes unpleasant free for all and it should be strongly discouraged.

best,
Evan Ludeman / T8